FixVibe
Covered by FixVibehigh

CORS Move konfigirasyon: Risk Politik ki twò permisif ZXCVFIXVIBESEGEN ZXCVFIXVIBESEG1 Aprann ki jan move konfigirasyon CORS pèmèt atakè yo kontoune Règleman sou menm orijin yo epi vòlè done itilizatè sansib nan aplikasyon entènèt ZXCVFIXVIBETOKEN1ZXCV ki te pwodwi yo. ZXCVFIXVIBESEGEN ZXCVFIXVIBESEG2 Pataje Resous Kwa Orijin (CORS) se yon mekanis navigatè ki fèt pou detann Règleman sou Menm Orijin (SOP). Pandan ke li nesesè pou aplikasyon entènèt modèn, move aplikasyon-tankou eko header Orijin moun ki fè demann lan oswa mete lis blanch orijin 'nil' la-ka pèmèt sit move eksfiltre done itilizatè prive. ZXCVFIXVIBESEGEN ZXCVFIXVIBESEG3 ## Enpak ZXCVFIXVIBESEGEN ZXCVFIXVIBESEG4 Yon atakè ka vòlè done sansib, otantifye nan men itilizatè yon aplikasyon vilnerab CORS. Si yon itilizatè vizite yon sit entènèt move pandan li konekte nan aplikasyon vilnerab la, sit move a ka fè demann kwa-orijin nan ZXCVFIXVIBETOKEN4ZXCV aplikasyon an epi li repons yo ZXCVFIXVIBETOKEN1ZXCVZXCVFIXVIBETOKEN2ZXCV. Sa a ka mennen nan vòl enfòmasyon prive, ki gen ladan pwofil itilizatè, marqueur CSRF, oswa mesaj prive ZXCVFIXVIBETOKEN3ZXCV. ZXCVFIXVIBESEGEN ZXCVFIXVIBESEG5 ## Kòz Rasin ZXCVFIXVIBESEGEN ZXCVFIXVIBESEG6 ZXCVFIXVIBETOKEN2ZXCV se yon mekanis ki baze sou tèt HTTP ki pèmèt sèvè yo presize ki orijin (domèn, konplo, oswa pò) yo pèmèt yo chaje resous CORS. Vilnerabilite anjeneral parèt lè politik ZXCVFIXVIBETOKEN3ZXCV yon sèvè a twò fleksib oswa mal aplike ZXCVFIXVIBETOKEN1ZXCV: ZXCVFIXVIBESEGEN ZXCVFIXVIBESEG7 * **Tèt orijin reflete:** Gen kèk serveurs li header CORS nan yon demann kliyan epi fè eko li tounen nan header repons ZXCVFIXVIBETOKEN1ZXCV (ACAO) ZXCVFIXVIBETOKEN2ZXCV. Sa a efektivman pèmèt nenpòt sit entènèt jwenn aksè nan resous ZXCVFIXVIBETOKEN3ZXCV. ZXCVFIXVIBESEGEN ZXCVFIXVIBESEG8 * **Kòd sovaj ki mal konfigirasyon:** Pandan ke kad CORS a pèmèt nenpòt ki orijin jwenn aksè nan yon resous, li pa ka itilize pou demann ki mande kalifikasyon (tankou bonbon oswa tèt otorizasyon) ZXCVFIXVIBETOKEN1ZXCV. Devlopè yo souvan eseye kontoune sa a pa dinamik jenere header ACAO ki baze sou demann ZXCVFIXVIBETOKEN2ZXCV. ZXCVFIXVIBESEGEN ZXCVFIXVIBESEG9 * **Whitelist 'null':** Gen kèk aplikasyon ki make orijin CORS, ki ka deklanche pa demann redireksyon oswa dosye lokal yo, ki pèmèt sit move yo maske kòm yon orijin ZXCVFIXVIBETOKEN1ZXCV pou jwenn aksè ZXCVFIXVIBETOKENXVIBETOKEN2CVIXVIXVXVXVXVXVZCVXCVFIX. ZXCVFIXVIBESEGEN ZXCVFIXVIBESEG10 * **Erè analiz:** Erè nan regex oswa matche kòd lè yo valide header CORS ka pèmèt atakè yo sèvi ak domèn tankou ZXCVFIXVIBETOKEN1ZXCV ZXCVFIXVIBETOKEN2ZXCV. ZXCVFIXVIBESEGEN ZXCVFIXVIBESEG11 Li enpòtan sonje ke ZXCVFIXVIBETOKEN1ZXCV se pa yon pwoteksyon kont Cross-Site Request Forgery (CSRF) CORS. ZXCVFIXVIBESEGEN ZXCVFIXVIBESEG12 ## Ranje konkrè ZXCVFIXVIBESEGEN ZXCVFIXVIBESEG13 * **Sèvi ak yon Lis Blan Estatik:** Evite dinamikman jenere tèt CORS nan tèt ZXCVFIXVIBETOKEN1ZXCV ZXCVFIXVIBETOKEN2ZXCV demann lan. Olye de sa, konpare orijin demann lan ak yon lis domèn ou fè konfyans ZXCVFIXVIBETOKEN3ZXCV. ZXCVFIXVIBESEGEN ZXCVFIXVIBESEG14 * **Evite orijin 'nil' la:** Pa janm mete CORS nan lis blanch ou ki gen orijin pèmèt ZXCVFIXVIBETOKEN1ZXCV. ZXCVFIXVIBESEGEN ZXCVFIXVIBESEG15 * **Restriksyon kalifikasyon:** Sèlman mete CORS si absoliman nesesè pou entèraksyon espesifik kwa-orijin ZXCVFIXVIBETOKEN1ZXCV. ZXCVFIXVIBESEGEN ZXCVFIXVIBESEG16 * **Sèvi ak Validasyon Apwopriye:** Si ou dwe sipòte plizyè orijin, asire lojik validation pou header CORS a solid epi yo pa ka kontourne pa soudomèn oswa domèn ki sanble ZXCVFIXVIBETOKEN1ZXCV. ZXCVFIXVIBESEGEN ZXCVFIXVIBESEG17 ## Kijan CORS teste pou li ZXCVFIXVIBESEGEN ZXCVFIXVIBESEG18 ZXCVFIXVIBETOKEN1ZXCV kounye a gen ladan l sa a kòm yon chèk aktif gated. Apre verifikasyon domèn, CORS voye demann ZXCVFIXVIBETOKEN2ZXCV ki gen menm orijin ak yon orijin atakè sentetik epi revize tèt repons ZXCVFIXVIBETOKEN4ZXCV. Li rapòte orijin abitrè ki reflete, ZXCVFIXVIBETOKEN5ZXCV ki gen kalifikasyon wildcard, ak ZXCVFIXVIBETOKEN6ZXCV ki byen louvri sou pwen final ZXCVFIXVIBETOKEN3ZXCV ki pa piblik pandan y ap evite bri byen piblik yo.

Cross-Origin Resource Sharing (CORS) is a browser mechanism designed to relax the Same-Origin Policy (SOP). While necessary for modern web apps, improper implementation—such as echoing the requester's Origin header or whitelisting the 'null' origin—can allow malicious sites to exfiltrate private user data.

CWE-942

Impact

An attacker can steal sensitive, authenticated data from users of a vulnerable application [S2]. If a user visits a malicious website while logged into the vulnerable app, the malicious site can make cross-origin requests to the app's API and read the responses [S1][S2]. This can lead to the theft of private information, including user profiles, CSRF tokens, or private messages [S2].

Root Cause

CORS is an HTTP-header based mechanism that allows servers to specify which origins (domain, scheme, or port) are permitted to load resources [S1]. Vulnerabilities typically arise when a server's CORS policy is too flexible or poorly implemented [S2]:

  • Reflected Origin Header: Some servers read the Origin header from a client request and echo it back in the Access-Control-Allow-Origin (ACAO) response header [S2]. This effectively allows any website to access the resource [S2].
  • Misconfigured Wildcards: While the * wildcard allows any origin to access a resource, it cannot be used for requests that require credentials (like cookies or Authorization headers) [S3]. Developers often try to bypass this by dynamically generating the ACAO header based on the request [S2].
  • Whitelisting 'null': Some applications whitelist the null origin, which can be triggered by redirected requests or local files, allowing malicious sites to masquerade as a null origin to gain access [S2][S3].
  • Parsing Errors: Mistakes in regex or string matching when validating the Origin header can allow attackers to use domains like trusted-domain.com.attacker.com [S2].

It is important to note that CORS is not a protection against Cross-Site Request Forgery (CSRF) [S2].

Concrete Fixes

  • Use a Static Whitelist: Avoid dynamically generating the Access-Control-Allow-Origin header from the request's Origin header [S2]. Instead, compare the request's origin against a hardcoded list of trusted domains [S3].
  • Avoid the 'null' Origin: Never include null in your whitelist of allowed origins [S2].
  • Restrict Credentials: Only set Access-Control-Allow-Credentials: true if absolutely necessary for the specific cross-origin interaction [S3].
  • Use Proper Validation: If you must support multiple origins, ensure the validation logic for the Origin header is robust and cannot be bypassed by subdomains or similar-looking domains [S2].

How FixVibe tests for it

FixVibe now includes this as a gated active check. After domain verification, active.cors sends same-origin API requests with a synthetic attacker origin and reviews CORS response headers. It reports reflected arbitrary origins, wildcard credentialed CORS, and wide-open CORS on non-public API endpoints while avoiding public asset noise.